Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16J—PISTONS; CYLINDERS; SEALINGS
  • F16J15/00—Sealings
  • F16J15/16—Sealings between relatively-moving surfaces
  • F16J15/34—Sealings between relatively-moving surfaces with slip-ring pressed against a more or less radial face on one member
  • F16J15/3496—Sealings between relatively-moving surfaces with slip-ring pressed against a more or less radial face on one member use of special materials
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
  • C04B35/52—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbon, e.g. graphite
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16J—PISTONS; CYLINDERS; SEALINGS
  • F16J15/00—Sealings
  • F16J15/16—Sealings between relatively-moving surfaces
  • F16J15/26—Sealings between relatively-moving surfaces with stuffing-boxes for rigid sealing rings
  • F16J15/30—Sealings between relatively-moving surfaces with stuffing-boxes for rigid sealing rings with sealing rings made of carbon
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16J—PISTONS; CYLINDERS; SEALINGS
  • F16J15/00—Sealings
  • F16J15/16—Sealings between relatively-moving surfaces
  • F16J15/34—Sealings between relatively-moving surfaces with slip-ring pressed against a more or less radial face on one member
• • G—PHYSICS
  • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
  • G21C—NUCLEAR REACTORS
  • G21C5/00—Moderator or core structure; Selection of materials for use as moderator
  • G21C5/12—Moderator or core structure; Selection of materials for use as moderator characterised by composition, e.g. the moderator containing additional substances which ensure improved heat resistance of the moderator
  • G21C5/126—Carbonic moderators
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E30/00—Energy generation of nuclear origin
  • Y02E30/30—Nuclear fission reactors

Definitions

• an aluminium phosphate in which the ratio of the nu'nibei' t' atoms of aluminium to the number of gram atoms of phosphorus is at least 1:1; and c. a dispersant for the binder.
• a dispersant for the binder the binder being present in an amount of 0.5 to 25 percent by weight of the composition.
• compositions may be used for a wide range of purposes and especially for moulding to produce shaped articles but also for purposes in which the hardening of the composition, its ready adherence to its star roundings and the heat-resistance of the product can be utilised. It may be used, for example as a mortar, cement or filler for example for binding ceramics or for high temperature applications for example in furnace walls and linings.
• the proportions of the components and the consistency of the mixes can be chosen to make them of optimum value for the use intended.
• the objects that may be formed from the compositions of the invention include electrodes, e.g. for electric furnaces such as those for producing steel; anodes for electrolysis cells, e.g. diaph agm chlorine cells, mercury cells, chlorate cells and fused salt cells for production of alkali metals, calcium and magnesium; brushes for rotors and dynamos; sleeves and thrust bearings; sealing and packing rings; electronic tube anodes and grids, nuclear reactor moderates, reflectors and thermal columns; rocket rotor nozzles; missile rudder vanes, carbon arcs; moulds, dies, furnace blazing rigs and crucibles; linings for furnaces etc; heatexchangers, diaphragms; leads, heads, nozzles, conducting paints e.g. for wall heating, and other conducting compositions, e.g. for underground or surfaceheating of roads, pathways and playing fields; and fibres.
• anodes for electrolysis cells e.g. diaph ag
• compositions may vary over a wide range. Suitable percentages by weight of the compositions for the components may be as follows:
• Binder 0.5 to 25% Dispersal" l to 50%
• the binder is present in an amount of 2 to 10% by weight of the composition.
• the weight ratio of graphite to binder may be from to 1:1.
• any grade of graphite may be used, the particular grade being chosen to suit the use to which the composition is to be put. If desired mixtures of different grades may be used. Examples of suitable grades include baked carbon, electrographite, impervious carbon and impervious graphite, electrode graphite, unpurified, thermally-purified and chemically-purified nuclear graphite, pyrographite and porous graphite.
• the complex phosphates which are particularly preferred are those in which the anionic group is a halogen, and preferably chlorine although the complexes may contain other halogens, for example bromine or iodine. These halogen containing complex phosphates are more fully described in U.S. Application No. 42,499 now Continuation Application No. 274,964 (corresponding to Dutch Application No. 70,08594).
• Other suitable complex phosphates are those in which the anionic group is other than halogen. Of this latter type, those in which the R is an organic group are more fully described in our U.S. Application 296,983 and those in which R is hydrogen are more fully described in U.S. Application No. 296,985. Examples of these other anionic groups include nitrate which is particularly preferred, sulphate, acetate, benzoate and perchlorate.
• R is an organic group
• aliphatic alcohols are especially preferred as the hydroxy compound since complex phosphates containing them are easily sepa-- rated solids obtainable in high yield.
• aliphatic alcohols containing one to ten carbon atoms are especially suitable, and owing to their ready availability we prefer to use aliphatic alcohols containing from one to four carbon atoms, for example, methanol, ethyl alcohol, n-propyl alcohol or isopropyl alcohol.
• the ratio of the number of gram atoms of aluminium to the number of gram atoms of phosphorus in the complex phosphate may vary over a wide range, for example, from 1:2 to 2:1, more especially 1:1 to 2:1 but is preferably substantially 1:1.
• the ratio of the number of gram atoms of aluminium to the number of gram atoms of halogen in the complex phosphates is preferably substantially 1:1.
• the complex phosphates may be monomeric or polymeric.
• the monomeric forms, or the repeating units of the polymeric forms of the complex phosphates may contain, for example, from one to five molecules of the hydroxy compound. Most frequently the number of molecules of the hydroxy compound is four. 1n some cases the complex phosphates may contain molecules of difl'erent hydroxy compounds, for example they may contain both chemically-bound water and a chemically-bound organic hydroxy compound, the total number of such molecules being, for example, from two to five.
• complex phosphates examples include:
• a particularly suitable halogen containing complex phosphate containing chemically bound water is that obtained by the process described in US. Application No. 245,196 in which aluminium orthophosphate hydrate' is contacted with a reactant gas comprising halogen-acid gas and/or a gaseous halogen.
• a reactant gas comprising halogen-acid gas and/or a gaseous halogen.
• the gas is hydrogen chloride and the hydrate AlPO,-3H O, a compound containing three molecules of water is obtained and having the empirical formula AlPClH-,O-,.
• aluminium phosphate When using aluminium phosphate itself it is generally desirable to use aluminium orthophosphate (MP0,) or its hydrates.
• the aluminium phosphate may be added as such to the composition or it may be formed in situ, for example, by dissolving or dispersing aluminium or a suitable compound in orthophosphoric acid.
• Suitable compounds include aluminium oxide or hydroxide or the aluminium salt of a volatile acid, e.g. aluminium nitrate, chloride, oxychloride or hydroxy chloride.
• the orthophosphoric acid may be mixed with a volatile acid, particularly when using aluminium or a compound other than the salts of the volatile acid.
• ysing phosphoric acid it is essential to avoid using a n-excess so that the Al:P ratio does not fall below 1:1.
• the dispersant generally a liquid dispersant, is preferably a solvent for the aluminium phosphate or complex although the binder may be dispersed in the dispersant, for example, as a suspension, sol or gel.
• the dispersant is not one which will change the A1:P ratio in the aluminium phosphate to less than 1:1.
• MPO aluminium orthophosphate
• Phosphoric acid which is commonly used for dissolving aluminium acid phosphates in known moulding compositions, is unsuitable since it would adversely affect the Al:P ratio.
• other solvents or dispersants may be included, particularly organic solvents, e.g. alcohols of 1 to carbon atoms.
• a refractory and/or ceramic material in the compositions, particularly when preparing objects for refractory uses, e.g. metallurgical crucibles, heads and nozzles.
• Suitable rwwramig naterials include coke; silica; alumina, e.g. tabular alumina and bauxite; magnesium and calcium oxides; zinc and tin oxides; magnesite; magchrome grog; zirconium silicate; zirconia; zircon; aluminium silicate, e.g. sillimanite, andalusite, kyanite, nullite and molochite; porcelain and china clays; carbides, e.g. silicon and tungsten carbide; nitrides, e.g.
• the weight ratio of refractory material to graphite may be for example from 5:1 to 1:10.
• Suitable metals include copper, lead, tin, zinc, aluminium and silver.
• the weight ratio of metal to graphite may be for example from 10:1 to 1:10.
• blowing agents there may be used any of the conventional agents such as fluorocarbon propellants and other volatile organic compounds as well as inorganic substances such as sulphur hexafluoride, carbon dioxide, argon or nitrogen.
• the blowing agent may be generated in situ.
• the binder is acidic, as for example it may be in the case of the complex phosphates, a basic substance such as magnesium carbonate, may be incorporated which will react with the complex phosphate on mixing in the dispersant.
• the dispersant is an organic liquid, reaction to form carbon dioxide is suitably controlled.
• a process for making a solid shape which comprises forming a shape from a composition of the invention and treating the formed shape to set it.
• an inert atmosphere e.g. nitrogen or argon.
• the shapes may be formed by extruding, pressing or moulding, e.g. by compression or jar moulding, a composition of the invention, preferably in the form of a paste.
• the density and strength of the solid shape is usually a function of the moulding pressure, which may vary, for example from 14 ltg/cm to 1,575 kg/cm, and also the firing temperature.
• the object to be formed is a fibre it is suitably prepared by forming a concentrated suspension of graphite particles in a non-aqueous solution of a linear organic polymer.
• desirable solvents include alcohols, glycols or halogenated hydrocarbons or mixtures of these, e.g. a mixture of methanol and chloroform. High boiling solvents may also be used to help preserve plasticity in the filament to be drawn.
• Suitable solvents include methyl cellulose.
• suitable polymers include polyvinyl butyral, polyvinyl formal and cellulose ethers e.g. hydroxypropyl cellulose.
• the binder, e.g. ACPE is added to the dispersion to form a paste.
• the polymer comprises 0.1 to by weight of the paste.
• the paste is then extruded through a spinnerette into a controlled atmosphere.
• the filament so formed is drawn down to a diameter less than the diameter of the filament leaving the spinnerette, thereby orientating the graphite.
• controlled atmosphere is anhydrous and suitably comprises air or nitrogen together with the solvent for the polymer.
• the invention also provides a dry formulation suitable for preparation of the compositions of the invention which comprises a mixture of graphite and a solid complex phosphate of aluminium (as herein described).
• the preferred complex phosphates are those designated ACPE and ACPH. These compounds are stable in air and so can fonn stable dry formulations which may be mixed with a suitable dispersant prior to use of the compositions of the invention.
• EXAMPLE 1 A synthetic graphite mixture was made up from graphite grades 0G1, -200 and 22A (ex Pitch Marketing Company Limited) in the ratio 10:20:70 by weight. 15g of the mixture were mixed with 2.5g w and l cc of water. The mixture was placed in a stainless steel mould and a pressure of 24.5 kg/cm applied. The
• the block was then removed from the mould and dried for 1 hour at C after which it was fired for 1 hour at 300C.
• the final block has a crushing strength of 42 ltg/cm and a specific gravity of 1.40.
• EXAMPLE 2 14g of molochite mix (45 parts of particle size 3.2 to 6.4 mm, 10 parts of particle size 0.25 to 0.5 mm of particle size less than 0.075 mm were mixed with 6g of the mixed synthetic graphite (as described in Example 1).
• EXAMPLE 4 To a mixture of 14g of the mixed molochite of Example 3 and 6g of the mixed synthetic graphite (as described in Example 1) was added 2g ACPE and 1.5g water. T he mixture was placed in a stainless steel mould and a pressure of 49 kg/cm applied. The block was removed from the mould and dried at 140C for 1 hour and then fired for 1 hour at 500C. The final block had a crushing strength greater than 44 kg/cm and a specific gravity of 1.79.
• compositions of the invention in producing graphite objects over prior art graphite materials include the fact that the objects can be fonned much more quickly, easily and at lower temperatures and the binder helps to protect the graphite against oxidation so that the objects can be used at higher temperatures than before.
• composition which comprises:
• a binder which is a complex phosphate of aluminium containing at least one chemically-bound molecule of a hydroxy compound, ROH, wherein R is selected from the group consisting of an organic group and hydrogen, and an anionic group selected from the group consisting of a strong inorganic acid, other than an oxyphosphorus acid, and a carboxylic acid; and
• a dispersant for the binder a dispersant for the binder; the binder being present in an amount of 0.5 to 25% by weight of the composition.
• composition according to claim 1 in which the binder is present in an amount of 2 to 10 percent by weight of the composition.
• composition according to claim 3 in which the ratio is substantially equal to 1:1.
• composition according to claim 1 in which the hydroxy compound of the complex phosphate is an aliphatic alcohol containing 1-4 carbon atoms.
• composition according to claim in which the alcohol is ethyl alcohol.
• composition according to claim 1 in which the anionic group is selected from the group consisting of a sulphate, acetate, benzoate, perchlorate and nitrate.
• composition according to claim 1 in which the anionic group of the strong inorganic acid is a halogen.
• composition according to claim 8 in which the halogen is chlorine.
• shape is formed by extruding, pressing or moulding.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Physics & Mathematics (AREA)
• Ceramic Engineering (AREA)
• Manufacturing & Machinery (AREA)
• High Energy & Nuclear Physics (AREA)
• Plasma & Fusion (AREA)
• Materials Engineering (AREA)
• Structural Engineering (AREA)
• Organic Chemistry (AREA)
• Ceramic Products (AREA)
• Curing Cements, Concrete, And Artificial Stone (AREA)

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Cited By (17)

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Citations (4)

• 1970
  • 1970-12-11 GB GB5903970A patent/GB1365287A/en not_active Expired
• 1971
  • 1971-11-22 CA CA128,280A patent/CA969977A/en not_active Expired
  • 1971-11-22 ZA ZA717844A patent/ZA717844B/xx unknown
  • 1971-11-29 AU AU36261/71A patent/AU456886B2/en not_active Expired
  • 1971-11-29 US US00203028A patent/US3804648A/en not_active Expired - Lifetime
  • 1971-11-30 PL PL1971151849A patent/PL81674B1/pl unknown
  • 1971-12-07 SU SU1723753A patent/SU431664A3/ru active
  • 1971-12-09 IT IT32175/71A patent/IT954200B/it active
  • 1971-12-09 NL NL7116931A patent/NL7116931A/xx unknown
  • 1971-12-10 LU LU64441A patent/LU64441A1/xx unknown
  • 1971-12-10 DE DE19712161468 patent/DE2161468A1/de active Pending
  • 1971-12-10 FR FR7144430A patent/FR2117639A5/fr not_active Expired
  • 1971-12-13 BE BE776631A patent/BE776631A/xx unknown

Patent Citations (4)

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